The present application relates to semiconductor devices, and more particularly to a method of forming a semiconductor structure that includes compressive strained silicon germanium alloy fins having a first germanium content and tensile strained silicon germanium alloy fins having a second germanium content that is less than the first germanium content on a same substrate.
For more than three decades, the continued miniaturization of metal oxide semiconductor field effect transistors (MOSFETs) has driven the worldwide semiconductor industry. Various showstoppers to continued scaling have been predicated for decades, but a history of innovation has sustained Moore's Law in spite of many challenges. However, there are growing signs today that metal oxide semiconductor transistors are beginning to reach their traditional scaling limits. Since it has become increasingly difficult to improve MOSFETs and therefore complementary metal oxide semiconductor (CMOS) performance through continued scaling, further methods for improving performance in addition to scaling have become critical.
The use of non-planar semiconductor devices such as, for example, semiconductor fin field effect transistors (FinFETs) is the next step in the evolution of complementary metal oxide semiconductor (CMOS) devices. Semiconductor fin field effect transistors (FETs) can achieve higher drive currents with increasingly smaller dimensions as compared to conventional planar FETs.
High percentage silicon germanium alloy fins (i.e., silicon germanium alloy fins having a germanium content of 50 atomic percent, %, or greater) are considered a front up option for future device nodes, like 7 nm and beyond. In order to achieve full advantage of high percentage silicon germanium alloy fins, the silicon germanium alloy fins must be strained. For CMOS devices, one needs tensile strained silicon germanium alloy fins for n-channel FETs (i.e., nFETs) and high percentage compressive strained silicon germanium alloy fins for p-channel FETs (i.e., pFETs), which are integrated on a same substrate. Applying strain solely through embedded stressor materials in the source region and the drain region does not work as desired, since the volume of the epitaxy in 10 nm and beyond technologies is too small to provide strain values needed to obtain desired performance targets.
In view of the above, there is still an ongoing need to provide tensile strained silicon germanium alloy fins and high percentage compressive strained silicon germanium alloy fins, which are integrated on a same substrate.